To configure quality of service

A page appears listing general
settings for quality of service, followed by a list containing the server
instance and each class of virtual servers.

To enable quality of service the server instance, click Enable.

By default quality of service is enabled. Enabling quality of service
increases server overhead slightly.

Choose the Recompute Interval.

The recompute interval
is the number of milliseconds between each computation of the bandwidth for
all servers, classes, and virtual servers. The default is 100 milliseconds.

Choose the Metric Interval.

The metric interval is
the interval in seconds during which the traffic is measured. The default
value is 30 seconds. All bandwidth measured during this time is averaged to
give the bytes per second.

If your site has a lot of large file
transfers, use a large value (several minutes or more) or this field. A large
file transfer might take up all the allowed bandwidth for a short metric interval,
and result in connections being denied if you’ve enforced the maximum
bandwidth setting. Since the bandwidth is averaged by the metric interval,
a longer interval smooths out spikes caused by large files.

If
the bandwidth limit is much lower than available bandwidth (for example, 1
MB-per-second bandwidth limit but with a 1 GB-per-second connection to the
backbone), the metric interval must be shortened.

Please note
that if you have large static file transfers and a bandwidth limit that is
much lower than available bandwidth, you have to decide which situation to
tune for, because the problems require opposite solutions.

Enable quality of service for the server instance and/or the virtual
server classes.

The lower portion of the screen lists the server
instance and server classes. Choose Enable as the action next to the items
for which you want to enable quality of service.

Set the maximum bandwidth, in bytes per second.

Choose whether or not to enforce the maximum bandwidth setting.

If you choose to enforce the maximum bandwidth, additional connections
are refused, once the server reaches its bandwidth limit.

If you
do not enforce the maximum bandwidth, server logs a message to the error log,
when the maximum is exceeded

Choose the maximum number of connections allowed.

This
number is the number of concurrent requests processed.

Choose whether or not to enforce the maximum connections setting.

If you choose to enforce the maximum connections, additional connections
are refused, once the server reaches its limit

If you do not enforce the maximum connections, when the maximum
is exceeded the server logs a message to the error log.